Placebo and nocebo effects in randomized double-blind clinical trials for fatigue in advanced cancer patients
Bibliographic record
Abstract
9640 Background: We have previously reported significant placebo response in randomized controlled treatment trials for cancer related fatigue (CRF). We conducted a retrospective study to determine the frequency and predictors of response to placebo and nocebo effect in patients with CRF. Methods: We reviewed patients that received placebo in two previous randomized clinical trials conducted by our group and determined the proportion of patients who demonstrated clinical response to fatigue using an increase (ΔFACIT-F score) > 7 from baseline to day 8, and those with nocebo response as those who reported side effects. Baseline patient characteristics and symptoms recorded from the Edmonton Symptom Assessment Scale (ESAS) were analyzed to determine their association with placebo and nocebo effects. Results: A total of 105 advanced cancer patients received placebo. 59 (56%) patients responded to placebo (median Δ FACIT-F score of 22). Worse baseline anxiety and well-being subscale score (univariate) and well-being (multivariate, MR) were significantly associated with placebo response. Common side effects reported were insomnia (79%), anorexia (53%), nausea (38%) and restlessness (34%). MR analysis showed that worse baseline (ESAS) sleep, appetite, nausea, and restless are associated with increased reporting of these side effects ( Table ). Conclusions: Nearly half of advanced cancer patients enrolled in the fatigue trials responded to placebo. Worse physical well-being score was associated with placebo response. Patients experiencing specific symptoms at baseline were more likely to report these as side effects of the medication. These findings should be considered in fatigue clinical trial design. [Table: see text] No significant financial relationships to disclose.
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How this classification was reachedexpand
Full frame machine prediction
Teacher imitationNot calibrated prevalence, not ground truth. Human validation pending. The Gemma side is a direct model label for every work in the frame, read from the title-only record. The Codex side is a classifier learned from the 10,348 direct Codex labels and calibrated to design-weighted sample rates; fields without enough sample support carry no Codex call. Candidate is the union of the two sides; consensus is their intersection. These outputs are machine_predicted_unvalidated and are not human labels.
Distilled classifier scores by category (both heads)
| Category | Codex | Gemma |
|---|---|---|
| Metaresearch | 0.046 | 0.063 |
| Meta-epidemiology (narrow) | 0.001 | 0.001 |
| Meta-epidemiology (broad) | 0.005 | 0.003 |
| Bibliometrics | 0.002 | 0.001 |
| Science and technology studies | 0.001 | 0.002 |
| Scholarly communication | 0.001 | 0.002 |
| Open science | 0.001 | 0.001 |
| Research integrity | 0.003 | 0.002 |
| Insufficient payload (model declined to judge) | 0.004 | 0.000 |
Machine scores (provisional)
The two teacher heads of the student model, read on this work. A score orders the frame for review; it never asserts a category, and the validation status ships verbatim with every row.
Baseline scores from an immature model (maturity gate not passed, 7 training rounds). Scores rank; they never assert a category.
score_only:v0-immature-baseline · verbatim from the scoring run: score_only means the number may rank works, and no category label ships from itClassification
machine, unvalidatedMachine predicted; a candidate call from one source (direct Gemma or distilled Codex), not a consensus.
How this classification was reached, model by model and score by score, is at the end of the page under "How this classification was reached".